Practice bomb

ABSTRACT

A practice bomb having a signal cartridge for locating the point of impact of said practice bomb after an airdrop and having means for arming the practice bomb during flight of said practice bomb by actuation of an arming pin connected to foldable fins which open upon high velocity of said practice bomb.

United States Patent Lohkam et al. [451 Jan. 18, 1972 [54] PRACTICE BOMB2,044,819 6/l936 Taylor ...102/4 2,l08,8l8 2193s 11 if t 1 10 7.6

[72] Inventors: Carl W. Lohkamp, Scotland; James E. 2'945439 7x960 g II232 3,343,486 9/!967 Patrick 102/716 [73] Assignee: The United Statesat America as represented by the Secretary of the Navy [22] Filed: July9, 1970 21 App]. No.: 53,609

[52] US. Cl. ..l02/7.6, 8911.5 D, 102/4 [51 Int. Cl. ..F42b 25/18 [58]Field of Search ..244/327, 329; 89/15 D; 102/4, l02/7.6

[56] References Cited UN [TED STATES PATENTS 1.357.927 ll/l920 Clarke..102L7 6 Primary Examiner-Samuel W. Engle Att0rneyR. S. Sciascia, H. H.Lcsche and Paul S. Collignon [5 7] ABSTRACT A practice bomb having asignal cartridge for locating the point of impact of said practice bombafter an airdrop and having means for arming the practice bomb duringflight of said practice bomb by actuation of an arming pin connected tofoldable fins which open upon high velocity of said practice bomb.

4 Claims, 4 Drawing F figures PRACTICE some STATEMENT OF GOVERNMENTINTEREST The invention described herein may be manufactured and used byor for the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION The present invention relates to a practicebomb which will provide a visual indication of the point of impact afteran airdrop, and more particularly to a practice bomb which becomes annedduring flight to provide maximum safety prior to launch from anaircraft.

Practice bombs which do not contain a large quantity of high explosivesare in general training use by the various military departments.Practice bombs are relatively inexpensive, as compared to highexplosivesbombs, and these bombs usually carry a small explosive charge to markthe point of impact of the practice bomb. Although the explosive chargein most practice bombs is not sufficiently large, various safetyprecautions must be taken to prevent accidental discharge of thesebombs. A premature detonation of a practice bomb on shipboard, forexample, could cause fuels or high explosives to ignite and create alarge peril to the ship and to those aboard. In order to prevent such anoccurrence, most practice bombs are maintained in a safe or unarmedcondition until the practice bomb separates from the launching aircraft.

By way of example, in US. Pat. No. 2,l08,8 l 8, which issued Feb. 22,1938, to Sargent P. Huff and Arthur Adelman, there is shown a practicebomb which remains in an unarmed condition until the practice bombseparates from the aircraft. A wire, which has one end attached to theaircraft, prevents movement of a bolt that extends between a firing pinand a cartridge. Upon launch of the practice bomb, the wire remains withthe aircraft, and the bolt moves to permit arming of the practice bomb.

The main objection to arming devices which arm weapons upon separationof the weapon from the carrying vehicle is that inadvertent launchingsalways drop anned weapons. For example, should either a high explosiveor practice bomb fall from an aircraft while taxiing across the deck ofan aircraft carrier, a highly dangerous condition arises if the bombbecomes armed due to the mere separation of the bomb from the aircraft.As many practice bombs detonate on impact, it is highly probable thatpractice bombs of the type shown in the aforesaid patent, would detonateif they were inadvertently dropped while an aircraft were taxiing.

SUMMARY OF THE INVENTION The present invention relates to a practicebomb which has foldable fins which unfold due to the high velocity ofthe bomb during a drop. A signal cartridge is provided in the bomb andis designed to be detonated upon impact of the bomb. The signalcartridge is maintained in a safe or unarmed condition, however, untilthe fins are unfolded. Thus a short fall, such as might occur duringtaxiing of an aircraft. will not be sufl'lcient to arm the practice bombof the present invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a side view, partially brokenaway, showing a preferred embodiment of the present invention;

FIG. 2 is a sectional view showing a signal cartridge and armingmechanism in a safe condition;

FIG. 3 is a view showing a practice bomb in a descent stage; and

FIG. 4 is a sectional view similar to FIG. 2 of the drawings onlyshowing an armed condition.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing,there is shown a practice bomb having a bomb case 1], foldable fins l2and an impactmarking section I3. As best shown in FIG. 3 of the drawing,fins 12 are designed to be opened by action of the airstream as thepractice bomb free falls from a launching aircraft. An arming pin 14 isprovided to maintain the impact-marking section 13 in a "safe" orunarmed condition. A cable I5 connects arming pin I4 with fins 12 sothat when fins 12 are unfolded pin 14 is withdrawn from section I3.

Referring now to FIGS. 2 and 4 of the drawing, the impactmarking section[3 has a body 16 having central bores 17 and 18 therein. A firing pindevice 19 threadedly engages and closes one end of bore 17 and has afiring pin tang 21 on the inner end thereof. A signal cartridge 22having a primer 23, a quantity of pistol powder 24, and a quantity ofphosphorus composition 25 is provided in signal cartridge 22. An inertiasleeve 26 is positioned around the outside of signal cartridge 22 andprovides additional momentum for signal cartridge 22 on impact of thepractice bomb. An arming stop pin 27 is slidably mounted through thewall of body 16 and, as shown in FIG. 2 of the drawing, protrudes intobore [7 between the forward end of signal cartridge 22 and the end offiring pin tang 21. It can readily be seen that, when in position asshown in FIG. 2 of the drawing, arming stop pin 27 prevents primer 23 insignal cartridge 22 from engaging firing pin tang 2I. A spring 28 isprovided for biasing arming stop pin 27 outwardly, however, movement ofarming stop pin 27 is prevented until rod 31 is withdrawn fromengagement with arming stop pin 27 and boss 32 on body 16. A spring 33in sleeve 34 is provided for withdrawing rod 31 from engagement witharming stop pin 27, however, movement of rod 3| is constrained by cotterpin 35 and arming pin 14. As best shown in FIG. 4 of the drawing, aspring 36 is provided around firing pin tang 2] to separate signalcartridge 22 from firing pin tang 2| until the time of impact of thepractice bomb.

OPERATION During storage and prior to loading onto a launching aircraft,cotter pin 35 is kept in position and keeps the practice bomb in a safecondition. The practice bomb is attached to the aircraft by means oflugs 37 and 38 with fins 12 being in a closed position, as shown in FIG.1 of the drawing. After loading into the bomb shackles, cotter pin 35 isremoved, however, the practice bomb is still in a "safe" condition, asarming stop pin 27 prevents contact between primer 23 in signalcartridge 22 and arming stop pin 27, is, in turn, retained in positionby rod 31.

Upon release of the practice bomb by the launching aircraft, theairstream causes fins 12 to open and arming pin 14 is withdrawn by cable15 which is attached to fins 12. Upon removal of arming pin 14, spring33 actuates rod 3! and rod 31 is withdrawn from engagement with armingstop pin 27. Spring 28 then moves anning stop pin 27 outwardly therebyclearing the path of signal cartridge 22. As signal cartridge 22 ispreferably loosely fitted in bores 17 and 18 of body 16, signalcartridge 22 moves forward and contacts spring 36, which prevents primer23 from engaging firing pin tang 21.

Upon impact of the practice bomb wifli the ground, or some target, themomentum of signal cartridge 22 causes primer 23 to strike firing pintang 2] and detonation of primer 23 causes ignition of pistol powder 24which, in turn, ignites phosphorus composition 25 to provide a visualindication of the point of impact of the practice bomb.

We claim:

I. A practice bomb comprising,

a bomb case,

fins pivotally attached to said bomb case and adaptable for opening uponlaunching of said practice bomb,

a firing pin stationarily mounted in said bomb case,

marking means slidably mounted within said bomb case and engageable withsaid firing pin for indicating the point of impact ofsaid bomb case, and

arming means connected to said fins for arming said prac' tice bomb uponopening of said fins.

ing means includes an arming stop pin positioned between said firing pinand said signal cartridge for preventing ignition of said signalcartridge until said fins open.

4. A practice bomb as set forth in claim 2 wherein an inertia sleeve isattached to said signal cartridge to facilitate movement of said signalcartridge upon impact of said practice bomb.

i l i I Q

1. A practice bomb comprising, a bomb case, fins pivotally attached tosaid bomb case and adaptable for opening upon launching of said practicebomb, a firing pin stationarily mounted in said bomb case, marking meansslidably mounted within said bomb case and engageable with said firingpin for indicating the point of impact of said bomb case, and armingmeans connected to said fins for arming said practice bomb upon openingof said fins.
 2. A practice bomb as set forth in claim 1 wherein saidmarking means comprises a signal cartridge having a primer, a quantityof smokeless powder and a quantity of phosphorus composition whereuponimpact of said practice bomb said primer strikes said firing pin therebyigniting said smokeless powder which in turn ignites and expels saidphosphorus composition.
 3. A practice bomb as set forth in claim 2wherein said arming means includes an arming stop pin positioned betweensaid firing pin and said signal cartridge for preventing ignition ofsaid signal cartridge until said fins open.
 4. A practice bomb as setforth in claim 2 wherein an inertia sleeve is attached to said signalcartridge to facilitate movement of said signal cartridge upon impact ofsaid practice bomb.